Preventive efforts to reduce urinary tract-related bloodstream infection are hampered by the scarcity of analytic studies that identify etiologic factors, particularly those specific to the time-dependent elements that may impact prognosis during hospitalization. Therefore, the ability of clinicians to intercede in a meaningful way has been restricted. The objective of this study is to delineate both host- and time-dependent factors that contribute to urinary tract-related bloodstream infection in hospitalized patients. This study is unique in that it will ascertain potential causal mechanisms of bloodstream infection taking into account the time course of a hospitalized patient's stay and the multiple procedures and treatments that occur during this stay. Specific Aim #1 addresses the relation between obesity, diabetes, and urosepsis. Specific Aim #2 is directed to time-related procedural and treatment factors that impact the incidence of infection. Of particular interest are the use of catheterization, ultrasound detection of urinary retention, antibiotics, immunosuppressant therapies, statin use, and allogeneic blood transfusions. A nested case-control study is planned that will include adult patients from the University of Michigan Health System. Incidence density sampling will be utilized for random selection of controls. Information from cases and controls will be extracted from multiple electronic databases (electronic medical, pharmacy, and laboratory records) over a 5-year period to yield 640 subjects. Analyses will identify factors related to the development of urinary tract-related bloodstream infection in hospitalized patients. Conditional logistic regression with clustering by ward will be utilized for the analyses, as well as sliding time windows for log-linear models and cubic B-splines with time-specific weight functions. We anticipate that the information obtained from the proposed study which evaluates novel risk factors and is responsive to program announcement PA-06-151 by utilizing secondary data will enhance tools for clinical decision making and provide a framework for preventive trials. Urinary tract infection is the most frequent healthcare-associated infection and, when disseminated to the bloodstream, can be fatal. The mortality rate of urinary tract-related bloodstream infection varies from 5% to 33% in different cohorts and is considerably higher in elderly patients. We anticipate that the information obtained from this study will form the foundation for the development of screening tests to identify patients at risk of infection at specific points in time during hospitalization and for planning preventive intervention trials. PUBLIC HEALTH RELEVANCE: Urinary tract infection is the most frequent healthcare-associated infection and, when disseminated to the bloodstream, can be fatal. The mortality rate of urinary tract-related bloodstream infection varies from 5% to 33% in different cohorts and is considerably higher in elderly patients. We anticipate that the information obtained from this study will form the foundation for the development of screening tests to identify patients at risk of infection at specific points in time during hospitalization and for planning preventive intervention trials.